1. Field of the Invention
The present invention relates to a process for improving the selectivity of a gas separation membrane wherein at least two monomeric materials are applied to the surface of the membrane and reacted with each other to effectively seal defects in the membrane.
2. Prior Art
U.S. Pat. No. 3,325,330 discloses a multicomponent gas separation membrane comprising a porous membrane coated with the lamination of two films.
U.S. Pat. Nos. 3,874,986 and 3,980,456 disclose a multicomponent gas separation membrane comprising a laminate on a porous substrate.
U.S. Pat. No. 4,230,463 discloses a multicomponent gas separation membrane comprising a coating on a porous membrane.
EPO 0 107 636 discloses a multicomponent gas separation membrane comprising a porous anisotropic substrate membrane and a coating which is the condensation product of a silanol terminated poly(dimethylsiloxane) and any of certain crosslinking compounds.
U.S. Pat. No. 4,575,385 discloses a multicomponent anisotropic substrate membrane and a coating of monomeric permeation modifiers.
U.S. Pat. No. 4,634,531 discloses a multicomponent reverse osmosis separation membrane comprising a porous anisotropic substrate membrane and a coating which is the condensation product of amines and aldehydes.
U.S. Pat. No. 4,654,055 discloses a multicomponent gas separation membrane comprising a porous anisotropic substrate membrane and a coating comprising a Lowry-Bronsted base.
U.S. Pat. No. 4,659,474 discloses multicomponent ultrafiltration and reverse osmosis separation membranes comprising a porous anisotropic substrate membrane and a coating which is the condensation product of a polyethylene imine and any of certain crosslinking compounds.
U.S. Pat. Nos. 4,613,625; 4,661,526; and 4,668,706 disclose a multicomponent ultrafiltration separation membrane comprising an aliphatic polyamide porous anisotropic substrate and a coating which is the condensation product of the substrate and any of certain crosslinking compounds.
U.S. Pat. No. 4,484,935 discloses a multicomponent gas separation membrane comprising a porous anisotropic substrate membrane and a coating which is the condensation product of reactive poly(dimethylsiloxane) with and any of certain crosslinking compound with modified silane monomers.
U.S. Pat. No. 4,505,985 discloses a multicomponent separation membrane comprising a porous substrate membrane and a coating based on silicic acid heteropolycondensates produced by hydrolytic-polycondensation of a silicic acid derivative in the presence of water with an optional condensation catalyst and modifiers.
Japanese Patent Publication, Kokai 57-94307 discloses a multicomponent reverse osmosis separation membrane comprising a dry composite semipermeable membrane treated with an aqueous surfactant solution.
Japanese Patent Publication, Kokai 61-107921 discloses a multicomponent gas separation membrane comprising a porous substrate and a coating which is the condensation product of a reactive acetylene monomer with a catalyst.
U.S. Pat. Nos. 4,259,183; 4,277,344; 4,643,829; 4,529,646; 4,520,044 and 4,661,254 disclose multicomponent reverse osmosis membranes comprising a porous anisotropic substrate and a coating which is the interfacial condensation product of amines and acid chlorides.